Leakage-tight joint



May 4, 1926.

- N.cRANE LEAKAGE TIGHT JOINT Filed DGO. 26, 1924 diffs.

m1 Z1 m2 Im/mier c foufim rmz v The object of the invention is to'provide al A111 the 30 b Fatented May 4, 1926.'

NEWTON CRANE, or BosT'oN,

MAssAcHusEr'rs, AssIGNoR 'ro wALWoR'rH-ENGI.Isrt v FLETT COMPANY, OFBOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

mannen-TIGHT JOINT.

Application led December 26, 1924.l Serial No. v.'5`x8,080.'

To all whom t may concern.'v

Be it known that I, NEWTONA CRANE, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented new and useful Improvements in Leakage-Tight. Joints, 0fwhich the following is a specification.

The present invention relates to packings for joints between pipes or inother conduits or containers in. which'V fluids may be con-` iined underhigh pressures.' Within the meaning of the term containers I includeclosed vesselsin which it maybe desired to which high pressures4 may beimposed or generated, as wel] as conduits.

packing or joint capable of being made tight so as to prevent leakage offluid, whether such fluid is liquid or gaseous, from the high pressureside to the low pressure sideof the joint, eventhough the pressuredifference may be of an order of magnitude amounting to many thousandsof pounds per square inch. of a. packing member of sufhciently hard andtough material to be itself not subject to flow under the fluidpressures encountered use of the joint, such packing memer being of aspecial form and vset into grooves, also of special form, in the membersof the joint, combined with coupling means adapted to close the membersof the'joint together and capable of exerting such great and uniformlydistributed lforce through said members upon the packing member as tocause flow of the latter into conformity with certain parts of thegrooves in which it is received. Thecharacteristics of the joint aremore particularly explained in the following specification, inconnection withpa drawing illustrating one embodiment of the inventionwith a modification in a. detail thereof. j

In the drawings:

Figure 1 isa longitudinal section of a joint between two lengths of 4apipe, such joint containing the principles of this invention; t

Fig. 2 is a similar view-of a like joint containing a modification indetails of construction; v

Fig. 3 is a perspective view of the pack ing ring which forms one of theelements of complete joint;

This object is accomplished by the use Fig. 4 is a fragmentary sectionalvie-w on an enlargedvsca-le of the members of my novel joint,illustrating the characteristic features thereof.l v

Like reference characters designate the same parts wherever they occurin all the gures. l

The' members a and b represent two pipe sections 4forming part of aconduit. In the `broader view they typify any two parts of a lcontainer,such as a closed receptacle and its cover, or any conduit in which fluidunder pressure is to be coniined.- Hence', although in the followingdescription I may refe-r to these members as pipes or pipefsections, theclaims are `,to be construed according to this broader view. Since theleakage-tight joint between the two members is the important subjectmatter of the invention, the character in other respects of the membersa and b themselves isv relatively unimportant.

Proceeding with the deemed description' of the embodiment'of theinvent-ion here illustrated, the pipe sectionsia and b are arranged endto end, and between j them is placed a packing ring c, whilethey arecon,- nected to one another, and drawn or pressed together, by -athreaded couplingv ring or nut d. In the species shown in Figure l theends of the pipe sectionsare thickened vby 'upsetting suiiiciently toprovide the necesfor cutting the screw threads with which the couplingnut engages, while.

sary material 1n the form shownl in Figure 2 the threads are cut uponrings or collars e and f suitably securedjto the pipe sections. Saidcollars orrings may be so secured by being shrunk on the ends of thepipe sections and thelatter expanded into bevels in the collars, or theymay be welded or brazed to the pipes, orattached in any other mannerwhich af'- fords suiiient securi y.

The threaded part of one of the pipes, whether formed on the thickenedend of the pipe itself or on a collar, is of larger diameter than thethreaded part of the other plpe; s o much so that the root of its thread1s of' larger diameter than the top of thel .thread on .thel other pipe;

pipe itself.. Thus the coupling nut,`

' interference of its smaller end with the taken up is the differentialpipe sections, and this differ# pressure threads on the pipe b (that is,the pipe having the thread of larger diameter).

The threads on the two pipe sections have respectively differentpitches; that is, one of'them has a greater number of turns per unit oflength than the other. In this case it is the thread a on thevpip-e oron its collar e which has the liner pitch,k and the thread b on the pipeb, or on its collar f which has the coarser pitch. Thus when thecoupling'nut is turned so as to screw it off from the pipe a and uponthe pipe b, it draws the pipes together with an effect equal to that ofa thread of which the pitch is 'the product of the pitches of threads aand b. To illustrate, in one specific design which I have made, in whichthe external diameters of the threads approximate seven and one-halfinches, I have made the thread a with a pitch of ,one-eighth of an inch,and the pitch of thread b with a pitch of oneseventh of an inch. Thismakes the closing effect of the coupling ring d equivalent to a screwhaving fifty-six threads to the inch, and enables great pressure to beexerted on the packing ring, while the threads are large enough to haveample strength. In other words, the amount by which the joint is of thethreads upon the two ential may be of any value desired; withoutsacrifice of strength in the threads. whereby enormous powers may bedeveloped in compression upon the packing ring. And as the couplingis anut completely encircling the pipe sections, this force is exertedequally at all points upon the packing ring.

r This last isan important factor in making a joint which isleakage-tight at all points under high pressures.

As ,the pipes and other containers are intended to withstand pressuresof great mag? nitude, for instance superheated steam at a of twelvehundred pounds per square inch, or other fluids in which even greaterpressures may be imposed from some source or generated by heat, the pipesections a and b, or equivalent members, and the coupling ring, arenecessarily made of a material and in dimensions capable of suchpressures. j I prefer to strength. The packing ring on, the other handis of softer material than the members a and b' (or e and f) but at thesame time hard and rigid enough not to flow under the pressures exertedupon it by the fluid. I mayhmake the packing ring ofofl iron,

for pressures of thehighest magnitudes, but -may use materials of .asomewhat more ductile quality as brass or copper, to serve conditionswhere the pressures are lower.

The formation of the packing ring and of the grooves in the othermembers of the joint in which it is set, is a vital factor of theinvention. As will be observed from the drawings, the packing ring isbeveled at both ends L and i, not necessarily to a sharp edge,'but to awidth or thickness less than that of the bottoms of the grooves in whichit is set, as will be presently explained. At its central zone j it ispreferably cylindrical, both externally and internally, although this isa characteristic in which some modiication is possible. Its form incross section is solid, by which I mean that it has no interior groovesor re-entrant angles capable of permitting its Abeveled sides to springtoward one another; and in composition it is substantially non-elasticand non-resilient'. In the adjacent ends of the pipe sections, or in thecollars e and f applied on said sections, are grooves Z and m whichapproximately match the beveled ends of the packing ring, but preferablydo not exactly match them, at their entrances, but at their bottoms Zand m are extended beyond the ends of the ring and have a width greaterthan the tapered extremities h and i thereof. The included angle.between the flaring sides of the grooves Z and m is less than ninetydegrees, but preferably slightly greater than the included angle betweenthe sides of the beveled ends of the ring. Thus between the Haring sidesof the grooves and ward and engaged with kthe threads of both sections.If, owing to the differential threads, it begins to bind before it hasbeen engaged fully enough with the threads, such bindingcan be relievedby turning the section a backward. When the nut is properly engaged withboth sections, it is turned, with the effect of forcing thesections-to-v gether, until the joint is tight. Under the great closingpressure therebyv exerted bctween the two-sections a and Z), the packingring is forced into tight engageinent iis with the" seating angles Z2,Z? and m2. mi',

and is caused to flow andv change its forni until it conforms toytheflaring sides of the grooves Z and m. Itis further -extruded intol thenarrow extensions Zt and;

at all nearly to do so,

grooves. Such deformation and extrusion insures a contact between thepacking ring.

and the walls of the grooves sufficiently tightto prevent leakage. I donot mean to imply that the packing ring is extruded so 'far as to lillthe grooveextensions, or

for that is not necessary or desired; but simply that suchextensions'provide spaces into which the'ends of the ring may beextruded far enough to cause its sides to conform exactly with the`seatingangles and with the flaring lsides of the grooves for asufiicient d1stance outside of such angles, w1thout requiring anyconsiderable upsetting or `thickening of the ring t-o take place.Inaccuracies in the form or finish of the ring are obliterated by thelocal deformation of the ring thus effected;

such local deformation being made pos-- sible and inevitable by the factthat the ring is not springy or resilient either, in composition orstructure.y I have used a packing having the characteristics heredescribed to withstand a pressure difference of approximately seventythousand pounds per square inch between the interior and ex,- terior ofthe container without any leakage occurring. y

In'achieving this result the. extrusion of the ends of the packing ringinto the groove extensions is an important factor; and to obtain thisaction it is necessary that such groove extension should be provided, ofa width greater than the extremities of the packing ring, and that theflaring sides of the grooves -should be of such an angle as will directthe flow of the ring intol these extensions rather than transverselybetween the ends of the coupled members a and For this reason I make the1ncluded angle between the flaring sides of the grooves less thanninetyfdegrees, and preferably about sixty degrees, with the oppositesides of the groove approximately symmetrical in respect to thedirection in which pressure is applied. Then in order to insure contactof the packing ring first with the seating shoulders Z2, Z2 and m2, m2,

the included angleof the beveled ends of the- 'ring is madeapproximately fifty-eight degrees, that is slightly less than theVincluded angle of the groove, and also symmetrical with respect to thedirection of closing pressure. Thus, under the great pressure applied inclosing together the parts of the joint, the packing ring is made toconform to the bearing contact shoulders of the grooves, and to theadjacent surfaces for sufficient distances outward therefrom, 4thusconforming to all minute irregularities and imperfections of thegrooves, v'and'thls leaving no passageway, however minute, through whichfluids underthe high pressures Ihere in contemplation can flow. Anymetal softer than the steel of which the members e and b are preferablymade, will flow in the' manner described and under the pressure exertedby means of the coupling nut, lbut the ring must b e of a strength andhardness such that it will ynot flow underv the pressures exerted' bythe fluid and so permit the fluid to open a passage for its escape. WhatI claim and desire to secure by Letters Patent is:

l. A container for fluid under high pres sure comprising separatemembers of hardness and rigidityl substantially as great as steelarranged adjacent to one another and having coaxial groovesin theiropposed surfaces, a packing ring of substantially nonresilient metal-and'construction and softer than said members but having strength andhardness at least as great as that of copper, said Aring having beveledends, and each of cluded angle than that of the adjacent beveled end ofthe ring, and *having also a 'bottom extension 'of extremity of thering; said ring being adapted to enter the said grooves and-t0 seat onthe angles between the beveledsides and the bottom extensions of therespective grooves; and means for forcing the said separate memberstoward one another with greater width than the pressure sufficient todistort the ring into,

exact conformity with said angles and with the beveled surfaces of saidgrooves next adjacent to said angles.

2. A container for high pressure comprising separate members ofrelatively hard metal arranged adjacent to one another with opposedannular surfaces, said surfaces having coaxial grooves equal in diameterto one another with beveled sides and bottom extensions, the sides ofwhich 'extensions form distinct angles with said beveled sides,

a packing ring having beveled ends adaptedV to enter the grooves of bothof said members, eac-h extremity of said ring being narrower thanthespace between the angles of the groove in eluded angle between itsbeveled sides being less than the angle between the beveled sides of thesame groove, the ring having a solid cross section and being composed ofnonresilient metal of a hardnessat least as great as copper, but lesshard than the said members, whereby it is locally`r deformable underpressure applied upon it byand through the angles of said grooves, andmeans for forcing the said members toward one another and against theinterpose ring with suilicient force to deform the beveled sides of saidring into conformity with the angles of the which it enters, and theinrespective` grooves, and to a progressive fexl adjacent to one anotherandhaving opposed annular surfaces in each of which is a groove coaxialand of-substantially equal diameter with a similar groove in the other,the said members being externally threaded with threads of respectivelydifferent pitches, a coupling nut having differential threadscoinplen'iental respectively to the threads of said members,` and apacking ring interposed betiveen said members and entering at itsopposite ends the respective grooves therein;v the said members beingsteel and the ring being made of a metal softer than steel butsubstantially equal in hardness to bottom extensions Wider than theextremitiesl of the rings, the sides of which extensions make distinctangles With the beveled sides of the respective grooves, and saidbeveled sides of the grooves including a .Wider angle than that betweenthe 4beveled. sides of the' ring.

In testimon);Y whereof I have affixed my slgnature.

NEWTON CRANE.

